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Custom Transactions

Icon LinkCustom Transactions

There may be scenarios where you need to build out transactions that involve multiple program types and assets; this can be done by instantiating a ScriptTransactionRequest . This class allows you to a append multiple program types and assets to a single transaction.

Consider the following script that transfers multiple assets to a contract:

script;
 
use std::asset::force_transfer_to_contract;
 
fn main(
contract_address: b256,
asset_a: AssetId,
amount_asset_a: u64,
asset_b: AssetId,
amount_asset_b: u64,
) -> bool {
let wrapped_contract = ContractId::from(contract_address);
 
force_transfer_to_contract(wrapped_contract, asset_a, amount_asset_a);
force_transfer_to_contract(wrapped_contract, asset_b, amount_asset_b);
true
}

This script can be executed by creating a ScriptTransactionRequest , appending the resource and contract inputs/outputs and then sending the transaction, as follows:

// #import { BN, CoinQuantityLike, ScriptTransactionRequest };
 
// 1. Create a script transaction using the script binary
const { minGasPrice } = contract.provider.getGasConfig();
 
const request = new ScriptTransactionRequest({
	...defaultTxParams,
	gasLimit: 3_000_000,
	script: scriptBin,
	gasPrice: minGasPrice,
});
 
// 2. Instantiate the script main arguments
const scriptArguments = [
	contract.id.toB256(),
	{ value: ASSET_A },
	new BN(1000),
	{ value: ASSET_B },
	new BN(500),
];
 
// 3. Populate the script data and add the contract input and output
request.setData(abiContents, scriptArguments).addContractInputAndOutput(contract.id);
 
// 4. Calculate the transaction fee
const { maxFee } = await provider.getTransactionCost(request);
 
// 5. Get the transaction resources
const quantities: CoinQuantityLike[] = [
	[1000, ASSET_A],
	[500, ASSET_B],
	[maxFee, BaseAssetId],
];
 
const resources = await wallet.getResourcesToSpend(quantities);
 
request.addResources(resources);
 
// 6. Send the transaction
const tx = await wallet.sendTransaction(request);
await tx.waitForResult();